1. Field of the Invention
This invention relates to a network device and a network connection establishing method, more particularly to a variable-frequency network device and a variable-frequency network connection establishing method.
2. Description of the Related Art
Generally, Ethernet connection rates are measured in units of ten, such as the connection rates of 10 Mbps, 100 Mbps, 1 Gbps, and 10 Gbps that are defined in Ethernet standard specifications. A network device must conform to one of these connection rates in order to establish a connection with a remote network device through an Ethernet network.
However, when these network devices are connected to a host, the connection rate is often restricted by a transmission rate of a data transmission interface (host interface) between the network devices and the host, since the transmission rate of the data transmission interface cannot be exactly the same as the connection rate at which the network devices themselves are capable of operating. For instance, the transmission rates of a PCI interface are 133 Mbps, 166 Mbps, etc., the bidirectional transmission rates of a PCI-E interface are 2.5 Gbps and 5 Gbps, and the transmission rate of a USB interface is 480 Mbps. As such, when the connection rate of the network device is different from the transmission rate of the data transmission interface, such as when the connection rate of the network device is 1 Gbps, and the transmission rate of the data transmission interface is that of the PCI interface, that is, 133 Mbps, the connection rate is restricted by the transmission rate of the data transmission interface. On the other hand, when the connection rate of the network device is for instance 2 Gbps, and the transmission rate of the data transmission interface is that of the PCI-E interface, that is, 2.5 Gbps, the transmission rate of the data transmission interface is restricted by the connection rate of the network device. The above-described situations thus result in inefficient utilization of either transmission rate capability or connection rate capability.